川南天然常绿阔叶林人工更新后枯落物层持水特性研究

Water Holding Characteristics of Litter Layer after Natural Evergreen Broadleaved Forest Artificial Regeneration in Southern Sichuan Province

对川南林区天然常绿阔叶林及其人工更新成檫木林、柳杉林和水杉林后林下枯落物层蓄积量、自然含水量和持水过程进行研究。结果表明:枯落物层蓄积量天然常绿阔叶林(25.68 t/hm2)>水杉林(18.14 t/hm2)>檫木林(9.95 t/hm2)>柳杉林(1.13 t/hm2)。天然常绿阔叶林枯落物层自然含水量分别是檫木林、柳杉林和水杉林的3.18倍、41.33倍和1.53倍。在整个持水过程中,前2 h内各林分枯落物层持水作用较强。林下枯落物层持水量与浸泡时间之间的关系式为Q=alnt+b,吸水速率与浸水时间之间的关系式为V=ktn。枯落物层最大持水量、最大拦蓄量和有效拦蓄量均是天然常绿阔叶林>水杉林>檫木林>柳杉林。因此,保护天然常绿阔叶林及其选择适宜的树种进行更新对于提高林下地表枯落物层水文生态功能具有重要的作用和意义。

This paper studied on the litter amount, natural water content and water holding characteristics of litter layer under the natural evergreen broadleaved forest and three artificial plantations, Sassafras tzumu, Cryptomeria fortunei and Metasequoia glyptostroboides forests, which formed by natural evergreen broadleaved forest artificial regeneration. The results showed that the amount of litter layer is natural evergreen broadleaved forest （ 25.68 t/hm^2） 〉 Metasequoia glyptostroboides forest （ 18. 14 t/hm^2） 〉 Sassafras tzumu forest （9.95 t/hm^2） 〉 Cryptomeria fortunei forest （1.13 t/hm^2）. The natural water content of whole litter layer in natural evergreen broadleaved forest is 3.18, 41.33, 1.53 times of that in Sassafras tzumu, Cryptcmeria fortunei and Metasequoia glyptostroboides forests, respectively. During the process of water holding of litter layer, the water holding capacity and absorption speed of the first 2 h were superior to the rest of time. The equation between the water holing capacity of the litter layer and the immerse time is Q = alnt ＋ b, the equation between the water absorption speed of the litter layer and the immerse time is V = kt＂. The maximum water holding capacity, the maximum interception and the modified interception of litter layer are natural evergreen broadleaved forest 〉 Metasequoia glyptostroboides forest〉 Sassafras tzumu forest〉 Cryptomeria fortunei forest. Therefore, protecting natural evergreen broadleaved forest and choose appropriate afforestation tree for artificial regeneration of natural evergreen broadleaved forest were important for enhancing the eco-hydrological benefits of forest litter layer.